The present invention relates to granular materials, particularly for sorbing organic materials especially solvents, oils and fats.
The present invention concerns, in particular, granules which are effective in sorbing organic material from a mixture of media containing the organic material, eg. organic material and water. The granules of the invention are useful, for example, for separating oil and other water immiscible pollutants from contaminated sea and river water and other aqueous bodies.
Many industries are faced with the problem of disposing of liquid wastes comprising a suspension or emulsion of an oily or water immiscible organic material in an aqueous medium. Environmental regulations forbid the discharge of such a liquid waste directly to a water course, and the waste must be treated in order to remove as completely as possible the organic material from the aqueous medium before the latter can be discharged to a convenient water course.
Various methods have been proposed for separating mixtures of water and organic pollutants. Many make use of an organoclay as the separating medium. An organoclay is generally a fine particulate, high surface area smectite or kandite clay, the surface of which has been rendered hydrophobic and oleophilic by treatment with a cationically active amine or quaternary ammonium compound which has at least one long chain alkyl group containing at least 8 carbon atoms. The positively charged nitrogen atom of such a reagent is attracted to, and bonds with, negative charges on the surface of the clay particles, while the long chain alkyl group extends outwardly from the surface of the clay particles and bonds with the molecules of the organic pollutants.
U.S. Pat. No. 2,367,384 (Tymstra) describes a method for removing small quantities of water-immiscible organic oily impurities from water. The method consists of contacting the oily composition with an inert solid coated with a cation surface-active bonding agent. The solid may be sand, clay, limestone, silica, rice hulls etc., and the cationic surface-active bonding agent may be a quaternary ammonium, phosponium or arsonium compound, a primary, secondary or tertiary amine, or a salt thereof.
U.S. Pat. No. 4,549,966 (Beall) describes a method for removing organic contaminants from an aqueous composition contaminated therewith. The method comprises contacting the aqueous composition with a sufficient amount of an organoclay for a sufficient length of time to absorb a substantial portion of the contaminant, and to form an aqueous organoclay admixture. The organoclay and aqueous composition are then separated from one another. The method is said to be particularly useful for separating oily contaminants such as humic acids and polychlorinated biphenyls from water contaminated therewith.